Characterization and performance of DLC films synthesized by plasma and ion beam techniques

Abstract

Diamond-like carbon (DLC) films have been deposited on dissimilar substrates using three different deposition processes. Two well-studied methods, employing cathodic arcs and rf-plasma self-bias, have been used. These two processes differ in that cathodic arc processes use gas pressures less than 1 mtorr and deposit atomic ions with energies less than 100 eV, while rf-plasma self-bias processes use gas pressures greater than 1 mtorr and deposit molecular ions with energies greater than 100 eV. In addition, DLC films have been deposited using a new plasma-based, pulsed-bias process. The pulsed-bias process uses gas pressures greater than 1 mtorr and deposits molecular ions with energies greater than 1,000 eV. Both the self-bias and pulsed-bias processes utilized hydrocarbon gases as the carbon source. Cathodic arc processes generally rely on the arc between two graphite electrodes as the carbon source. Deposited films from all three processes have been characterized using ion backscattering techniques, Elastic Recoil Spectrometry (ERS), Transmission Electron Microscopy (TEM) and Selected Area Diffraction (SAD). Films deposited using the cathodic arc process are virtually hydrogen free while the self-bias and pulse-bias films contain up to 40% hydrogen. TEM results indicated the films are homogeneous and amorphous. The hardness, elastic modulus, coefficient of friction and wear rate of the films are also reported.